Inductively coupled plasma (ICP) spectrometry is an analysis technique commonly used to determine trace element concentrations and isotope ratios in liquid samples. ICP Spectrometry employs electromagnetically generated partially ionized argon plasma which reaches a temperature of approximately 7000K. When a sample is introduced to the plasma, the high temperature causes sample atoms to become ionized or emit light. Since each chemical element produces a characteristic mass or emission spectrum, measuring the spectra of the emitted light allows the determination of the elemental composition of the original sample.
Sample introduction systems may introduce liquid samples into ICP spectrometry instrumentation (e.g., an inductively coupled plasma mass spectrometer (ICP/ICPMS), an inductively coupled plasma atomic emission spectrometer (ICPAES), or the like, for analysis. For example, a sample introduction system may withdraw an aliquot of a liquid sample from a container and thereafter transport the aliquot to a nebulizer that converts the aliquot into a polydisperse aerosol suitable for ionization in plasma by ICP spectrometry instrumentation. The aerosol is then sorted in a spray chamber to remove larger aerosol particles. Upon leaving the spray chamber, the aerosol enters the ICPMS or ICPAES instrument for analysis. Often, the sample introduction is automated, introducing large numbers of samples into the ICP spectrometry instrumentation in an efficient manner. However, automated sample introduction mechanisms are limited because sample introduction systems can only collect and introduce one sample at a time. The inability of conventional sample introduction systems to simultaneously process more than one sample limits the overall throughput of the system.
Consequently, it would be advantageous if an automated sample introduction apparatus existed that was suitable for collecting and introducing more than one liquid sample at a time.